The present invention relates to a parallel operation power supply control system.
In the conventional parallel operation power supply control system, each of switching power supply modules operated in parallel to one another is provided with an output voltage trailing circuit having an operating point at vicinity of a rating output current. This output voltage trailing circuit operates when an output current of the corresponding switching power supply module exceeds a rating output current for lowering the output voltage at the vicinity of the rating output current region so as to avoid overflow of the output current above the rating value.
In the conventional parallel operation power supply control system utilizing the output voltage trailing circuit, the output currents of the respective switching power supply modules connected in parallel to one another are not balanced with each other. Therefore, a particular switching power supply module tends to continuously flow a great amount of electric current, and receives an excess load, thereby causing a drawback in view of the reliability.
Further, when balancing the output currents among a plurality of switching power supply modules, there is caused a drawback in that current regulation is complicated and time-consuming because of a very small value of the output impedance below the rating output current value. In addition, there is another drawback that the output voltage of the switching power supply module is not stable after the regulation.